INFO: rcu detected stall in sys_sendfile64

[Tetsuo Handa]

On 2018/12/19 18:27, syzbot wrote:
> HEAD commit:    ddfbab46539f Merge tag 'scsi-fixes' of git://git.kernel.or..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=15b87fa3400000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=861a3573f4e78ba1
> dashboard link: https://syzkaller.appspot.com/bug?extid=bcad772bbc241b4c6147
> compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13912ccd400000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=145781db400000

This is not a LSM problem, for the reproducer is calling
sched_setattr(SCHED_DEADLINE) with very large values.

  sched_setattr(0, {size=0, sched_policy=0x6 /* SCHED_??? */, sched_flags=0, sched_nice=0, sched_priority=0, sched_runtime=2251799813724439, sched_deadline=4611686018427453437, sched_period=0}, 0) = 0

I think that this problem is nothing but an insane sched_setattr() parameter.

#syz invalid